Strain

(1) Function: noun
Etymology: Middle English streen progeny, lineage, from Old English strEon gain, acquisition; akin to Old High German gistriuni gain, Latin struere to heap up -- more at STREW
1 a : LINEAGE, ANCESTRY b : a group of presumed common ancestry with clear-cut physiological but usually not morphological distinctions <a high-yielding strain of winter wheat>; broadly : a specified infraspecific group (as a stock, line, or ecotype) c : KIND, SORT <discussions of a lofty strain>
2 a : inherited or inherent character, quality, or disposition <a strain of madness in the family> b : TRACE, STREAK <a strain of fanaticism>
3 a : TUNE, AIR b : a passage of verbal or musical expression c : a stream or outburst of forceful or impassioned speech
4 a : the tenor, pervading note, burden, or tone of an utterance or of a course of action or conduct b : MOOD, TEMPER

(2)Function: verb
Etymology: Middle English, from Anglo-French estreindre, from Latin stringere to bind or draw tight, press together; akin to Greek strang-, stranx drop squeezed out, strangalE halter
transitive verb
1 a : to draw tight : cause to fit firmly <strain the bandage over the wound> b : to stretch to maximum extension and tautness <strain a canvas over a frame>
2 a : to exert (as oneself) to the utmost b : to injure by overuse, misuse, or excessive pressure <strained his back> c : to cause a change of form or size in (a body) by application of external force
3 : to squeeze or clasp tightly: as a : HUG b : to compress painfully : CONSTRICT
4 a : to cause to pass through a strainer : FILTER b : to remove by straining <strain lumps out of the gravy>
5 : to stretch beyond a proper limit <that story strains my credulity>
6 obsolete : to squeeze out : EXTORT
intransitive verb
1 a : to make violent efforts : STRIVE <has to strain to reach the high notes> b : to pull against resistance <a dog straining at its leash> c : to contract the muscles forcefully in attempting to defecate -- often used in the phrase strain at stool
2 : to pass through or as if through a strainer <the liquid strains readily>
3 : to make great difficulty or resistance : BALK
- strain a point : to go beyond a usual, accepted, or proper limit or rule

(3) Function: noun
1 : an act of straining or the condition of being strained : as a : bodily injury from excessive tension, effort, or use <heart strain>; especially : one resulting from a wrench or twist and involving undue stretching of muscles or ligaments <back strain> b : excessive or difficult exertion or labor c : excessive physical or mental tension; also : a force, influence, or factor causing such tension <a strain on the marriage> d : deformation of a material body under the action of applied forces
2 : an unusual reach, degree, or intensity : PITCH
3 archaic : a strained interpretation of something said or written